March 11, 1955

This evening, as one week earlier, and even more so, Einstein was of
unusual concentration. We read the second half of my paper On the
Four Systems of the World. We sat at the round low table in his
study, he at my left, not in an easy chair as he was wont, light shining
on the paper that we read passage after passage, stopping and discussing.
We started at 8:30 and continued till after 11:15, for two and three quarter
hours. This time, in order to keep Miss Dukas awakeher fatigue was
usually the cause of our breaking upI brought with me the first
of the three triple-ring binders with Stargazers and Gravediggers,
the story of the suppression of Worlds in Collision; I did not
intend it for Einstein but for her, to have my discussion with Einstein
unburdened by the usual sight of Dukas, vivid at the beginning of a session,
but tired after a day of the many chores of both the household and the
secretarial work, when it was close to eleven oclock. She and my
wife were regularly present at our meetings, she (Dukas) rarely leaving
the room. She was usually interested in what was talked about, but not
in physical problemsand on one of the previous evenings, when Einstein
and I were concentrating on reading my paper, she said to my wife: Dies
sind für mich Bömische Wälderor These
to me are Bohemian forestsimpenetrable woods with no path
through them, an expression of utter unfamiliarity with a subject. For
an intelligent person associated with Einstein for twenty-five years this
actually was a bit of insecurity that should have been overcome; it is
a fact that she could carry on intelligently Einsteins correspondence.

Now she was immersed in reading the account of my experiences. In the
quiet atmosphere of the evening, with no exchange of sentences between
Dukas and Elisheva, no telephone calls, no doorbell rings, Einstein and
I took up passage by passage. That evening we read the third and fourth
systems. The third systemthe one which has the sun, planets, and
satellites carrying static electrial charges, providing the mechanism
of attraction, was included for the sake of completeness; the argument
that if the sun attracts the earth because of the opposite signs of their
charges, it would repel the moon which, in such a plan must have a charge
of a sign opposite to that of the earth, but of the same sign as the sun,
disposes of this system; it is an obvious argument, and it was also used
by Einstein in one of his letters when he did not suspect that my own
interpretation of the electromagnetic effects in the solar system was
similar at least in some respects to a rather different model, which model
was presented as the fourth system. According to it, the central bodythe
suncarries an appreciable charge, and by rotating creates an extended
electromagnetic field; charged planets move through the fieldor
are carried by it; those that rotate create magnetic fields and their
satellites move through them; their motion is counterclockwise, or clockwise,
depending at least in some cases upon the sign of the charge.

Einstein was obviously greatly interested and intrigued by the fourth
model. When reading the text we encountered the issue of the decrease
of the intensity of a field issuing from a dipole, as the inverse cube
of the distance, which would require a greater charge for planets more
remote from the sun in order that the overall effect should still follow
the inverse square law, and by way of analogy I mentioned that this is
the arrangement in the atom, where the electrons on external orbits carry
more energy than those on internal orbits; Einsteins face immediately
lightedhe was obviously struck by the analogy. This lighting of
the face I observed twice that evening: it was as if a hunter suddenly
perceived his game.

"And why do you need gravitation at all? asked he, obviously
fascinated by the model. But immediately he corrected himself: Oh
yes, in order to account for the phenomena on earth.

It is immaterial whether Einstein thought, as it appeared to me, that
there could be truth in this system of the world; as a theoretician he
was obviously fascinated by the model. It certainly appealed to him as
a construction. Actually, I was presenting him with what I challenged
him to produce at a meeting over a year earlier: I gave you, Albert
Einstein, a very unusual mind and, what is still rarer, the recognition
and admiration of your contemporaries: Now build a working plan for another
universe; only dont apply gravitation that propagates at the inverse
square, but electricity and magnetism you may use as much as you need.
And why do you need gravitation? he soon asked again, and
again trapped himself"yes, because of the terrestrial phenomena.

For the second time his face uprighted and lighted up when I mentioned
that in this system the satellites, depending in part on the sign of their
charge, revolve directly (counterclockwise) or retrogradely (clockwise).

His concentration that evening, the omission of counter-argument on his
part, usual in our debates, and the great delight that he experienced
in reading for three hours the few pagesthe second halfof
my paper, made us feel closer to each other than at any other meeting.
And it was this that made him say at the end of that evening: I
think that it is a great error that the scientists do not read your bookthere
is much that is important in it ; and even more, that made him confess
to me that among the scientists he had met during his lifetime he valued
completely, as a human being, only one manLorentz of Holland, all
others having shown human deficiencies. He expressed himself strongly,
and it was a surprise to me that he, regarded by all as so humane and
so forgiving, in his unique position which brought him recognition and
admiration from everybody, should be so severe a judge of the human nature
of all the scientists he knew, famous and obscure. He was standing, animated,
telling me what, possibly, he had never said to any outsider; yet Miss
Dukas, who was kept awake during the quiet evening by reading my Stargazers,
now by her response to Einsteins words displayed her knowledge of
his attitude. Experience had taught him to regard his fellow men with
suspicion and to see their moral inadequaciesit sounded almost as
if he were a misanthrope, and this suprised me greatly; but I also felt
that he was taking me into his confidence as he had possibly never taken
anybody of the outside world. He was certainly very good to me that evening;
I felt some tie of great tenderness, and goodwill, and confidence.

"A theory, he said, has a much greater chance for acceptance
if it can predict a phenomenon ; with these words he parted with
me and then he went down the stairs to the door to press my hand again;
he said also something about how he enjoyed the evening with me. In his
words about a theory attaining success if it can predict a phenomenon
was clearly a wish that I should be able to produce such a prediction,
and there sounded a sincere desire that my theory should prove true.

I felt as if Einstein blessed me that night. And he said, Let me
go, for the day breaketh. And he said, I will not let thee go, except
thou bless me. I probably did not think of these words that I had
sent him several months earlier; but I felt an achievement: after all
these months of debate about the participation of electromagnetic forces
in the working of the universe, now for the first time I had made him
understand how I envisaged the plan. The classical plan was compromised
by evidence; the static electricity plan did not stand up against argument;
but the other two plansin both of which electromagnetic effects
take part in varying degreesvie for the position of the true system
of the world. Now he knew that I was not contemplating a model in which
electromagnetism played a static role of attraction and repulsion, but
one in which it played predominantly a dynamic role. I presented my discourse
in the dispassionate terms of a brief review of four contestants, and
left it to reason, calculation, and experiment to make the selection.

The magnetic field of the earth, the origin of which is a mystery, would
be a direct effect of a charged body in rotation; the great, almost unimaginable
energies measured in billion billion electron volts with which some cosmic
rays approach the earth could be explained by the magnetic field in space
but especially by the charge of the earthand in consequence, the
linear acceleration experienced by these ray-particles.